The present invention relates to the treatment of and mass transfer in mixtures of liquid and gases.
In such methods liquid and gas are brought into contact with each other to provide mass transfer between the phases. Subsequently the phases are separated.
From Norwegian Pat. No. 152,209 is known a method where an inert gas is employed to separate an unwanted gas from a gas/liquid mixture by stripping. The inert gas is separated from the liquid, regenerated and purified in the gaseous state by means of a catalyst and thereafter recirculated. The liquid is transported by simultaneously pumping and stripping utilizing a so-called "gas lift effect" through a vertical tube.
Utilizing the gas lift principle for pumping and mass transfer in a vertical tube, a flow pattern for gas and liquid is created and this pattern will vary within the tube. By choosing an optimal gas volume to obtain satisfactory mass transfer in a tube of a length of 100 m, it was found that an increase in the amount of gas beyond the optimal functioning of the gas lift effect was not advantageous. A further increase of the gas volume resulted in ring flow in significant areas of the tube and reduced effectively the total liquid flow and the gas lift effect. Therefore there is no freedom available to choose gas/liquid ratios which results in both optimal mass transfer and efficient pumping simultaneously.